It seems entirely revealing, if dispiriting, that the days before the July Fourth holiday showed Red America and Blue America pulling apart at an accelerating rate.

Of all of our national holidays, Independence Day is the one most intimately rooted in our common history and shared experience. Yet this year it arrives against a background of polarization, separation, and confrontation in the states and Washington alike. With municipal politics as the occasional exception, the pattern of solidifying agreement within the parties -- and widening disagreement between them -- is dominating our decisions at every level.

On almost all of our major policy choices, the common thread is that the election of 2012 did not "break the fever" of polarization, as President Obama once hoped it might. Last November, Obama became only the third Democrat in the party's history to win a majority of the popular vote twice. But congressional Republicans, preponderantly representing the minority that voted against Obama, have conceded almost nothing to his majority -- leaving the two sides at a stalemate. Meanwhile, beyond the Beltway, states that lean Democratic and those that lean Republican are separating at a frenetic pace.

Consider a few recent headlines. The Supreme Court decision upholding the lower-court invalidation of California's Proposition 8 restored gay marriage in the nation's largest state. It also capped a remarkable 2013 march for gay marriage through blue states, including Delaware, Minnesota, and Rhode Island (with Illinois and New Jersey possibly joining before long). The consensus is solidifying fast enough that 2014 could see several blue-state Republican gubernatorial candidates running on accepting gay-marriage statutes as settled law. Former California Lt. Gov Abel Maldonado, a likely 2014 GOP gubernatorial contender who this week reversed his earlier opposition to support gay marriage, may be an early straw in that breeze.

The story in red states, though, remains very different. Almost all of them have banned gay marriage. Some activists believe Justice Anthony Kennedy's embrace of equal-protection arguments in the decision striking down the federal Defense of Marriage Act might enable litigation challenging those bans; but if not, it may take a very long time for the support for gay marriage among younger voters to dissolve the resistance to the idea in culturally conservative states. Absent further Supreme Court action, the nation could remain a "house divided" on gay marriage for longer than many may expect: The high court's ruling striking down the remaining 16 state laws banning interracial marriage came in 1967 -- nearly two centuries after the first state had revoked its ban (Pennsylvania in 1780).

Meanwhile, as gay marriage advances in blue states, red states are competing to impose the tightest restrictions on abortion since the Supreme Court established the national right to it in Roe v. Wade. In Ohio this week, Republican Gov. John Kasich signed legislation requiring ultrasound exams before abortions, effectively cutting off funding for Planned Parenthood and making it more difficult for abortion providers to transfer patients to public hospitals. In Texas, after the dramatic filibuster by Democratic state Sen. Wendy Davis temporarily disrupted his plans, Republican Gov. Rick Perry this week opened another legislative special session that is likely to ban abortion at 20 weeks and impose stringent new safety requirements that would shutter most of the state's abortion providers. All of this follows a cascade of legislation restricting abortion in Republican-run states from Arkansas and Louisiana to Kansas and North Dakota -- most of which are already facing legal challenges.

In Washington, there's little sign of convergence. Hopes for a budget "grand bargain" are flickering. In the Senate, the two parties have worked together to pass a farm bill, and more dramatically a sweeping immigration overhaul that won support from all 54 Democrats and 14 Republicans. But House Republicans, who recently collapsed into chaos when they couldn't pass a farm bill, are pledging to block any reform that includes a path to citizenship for illegal immigrants -- an indispensable component of legislation as far as Democrats are concerned. On big issues, the Supreme Court looks just as chronically divided, and the split often comes down to Republican- and Democratic-appointed justices.

All of this reveals a political system losing its capacity to create common ground between party coalitions divided along economic, racial, generational, and even religious lines. Some variation in state policy is healthy, but states are now diverging to an extent that threatens to undermine equal protection under the law. The stalemate in Congress reflects genuine differences, but the reluctance to compromise -- most intractable among House Republicans -- prevents us from confronting common challenges.

In all these ways, our contemporary politics is ignoring the simple truth that none of us are going away -- not the cosmopolitan coasts, nor the evangelical South. Our choices ultimately come down to bridging our differences or surrendering to endemic separation in the states and stalemate in Washington. This week we celebrate the moment when the authors of the Declaration of Independence concluded they had no choice but "to dissolve the political bands which have connected them with another." It's an excellent opportunity to consider how ominously our own "political bands" are fraying.

Ronald Brownstein, a two-time finalist for the Pulitzer Prize for his coverage of presidential campaigns, is Atlantic Media's editorial director for strategic partnerships, in charge of long-term editorial strategy. He also writes a weekly column and regularly contributes other pieces for the National Journal, contributes to Quartz, and The Atlantic, and coordinates political coverage and activities across publications produced by Atlantic Media.